Hodgkin lymphoma as Richter transformation in chronic lymphocytic leukaemia: a retrospective analysis of world literature.

Richter transformation in chronic lymphocytic leukaemia (CLL) represents an entity of considerable genetic, molecular, immunological and clinical heterogeneity. A rare occurrence, Hodgkin variant of Richter syndrome, has not been comprehensively characterized or systematized to date. We conducted a retrospective analysis of the existing cases of Hodgkin lymphoma as Richter syndrome reported in the medical literature in the previous three and a half decades. Our search identified 86 such patients; this entity affects predominantly older men and the most common histological subtype is mixed cellularity. Interval between the diagnosis of CLL and subsequent development of Hodgkin lymphoma is circa 4.3 years. The overall survival of patients was approximately 1.7 years in our analysed cohort. However, our pooled data showed that patients in whom CLL had been treated with fludarabine had a shorter survival after transformation compared to the ones not treated with this agent. The role of immunosuppression and Epstein-Barr virus infection in the aetiopathogenesis of this entity remains to be clarified.